diff --git a/samples/server/petstore/rust-server/output/openapi-v3/docs/ObjectUntypedProps.md b/samples/server/petstore/rust-server/output/openapi-v3/docs/ObjectUntypedProps.md
index 44919a9b60a..e8af6d7c8f8 100644
--- a/samples/server/petstore/rust-server/output/openapi-v3/docs/ObjectUntypedProps.md
+++ b/samples/server/petstore/rust-server/output/openapi-v3/docs/ObjectUntypedProps.md
@@ -3,10 +3,10 @@
 ## Properties
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-**required_untyped** | [***serde_json::Value**](object.md) |  | 
-**required_untyped_nullable** | [***serde_json::Value**](object.md) |  | 
-**not_required_untyped** | [***serde_json::Value**](object.md) |  | [optional] [default to None]
-**not_required_untyped_nullable** | [***serde_json::Value**](object.md) |  | [optional] [default to None]
+**required_untyped** | [***AnyType**](.md) |  | 
+**required_untyped_nullable** | [***AnyType**](.md) |  | 
+**not_required_untyped** | [***AnyType**](.md) |  | [optional] [default to None]
+**not_required_untyped_nullable** | [***AnyType**](.md) |  | [optional] [default to None]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/server/petstore/rust-server/output/openapi-v3/src/models.rs b/samples/server/petstore/rust-server/output/openapi-v3/src/models.rs
index 19c8a7d633f..57b9fc04c45 100644
--- a/samples/server/petstore/rust-server/output/openapi-v3/src/models.rs
+++ b/samples/server/petstore/rust-server/output/openapi-v3/src/models.rs
@@ -1245,23 +1245,23 @@ impl From<hyper::header::HeaderValue> for header::IntoHeaderValue<ObjectUntypedP
 #[cfg_attr(feature = "conversion", derive(frunk::LabelledGeneric))]
 pub struct ObjectUntypedProps {
     #[serde(rename = "required_untyped")]
-    pub required_untyped: serde_json::Value,
+    pub required_untyped: AnyType,
 
     #[serde(rename = "required_untyped_nullable")]
-    pub required_untyped_nullable: serde_json::Value,
+    pub required_untyped_nullable: swagger::Nullable<AnyType>,
 
     #[serde(rename = "not_required_untyped")]
     #[serde(skip_serializing_if="Option::is_none")]
-    pub not_required_untyped: Option<serde_json::Value>,
+    pub not_required_untyped: Option<AnyType>,
 
     #[serde(rename = "not_required_untyped_nullable")]
     #[serde(skip_serializing_if="Option::is_none")]
-    pub not_required_untyped_nullable: Option<serde_json::Value>,
+    pub not_required_untyped_nullable: Option<AnyType>,
 
 }
 
 impl ObjectUntypedProps {
-    pub fn new(required_untyped: serde_json::Value, required_untyped_nullable: serde_json::Value, ) -> ObjectUntypedProps {
+    pub fn new(required_untyped: AnyType, required_untyped_nullable: swagger::Nullable<AnyType>, ) -> ObjectUntypedProps {
         ObjectUntypedProps {
             required_untyped: required_untyped,
             required_untyped_nullable: required_untyped_nullable,
@@ -1299,10 +1299,10 @@ impl std::str::FromStr for ObjectUntypedProps {
         #[derive(Default)]
         // An intermediate representation of the struct to use for parsing.
         struct IntermediateRep {
-            pub required_untyped: Vec<serde_json::Value>,
-            pub required_untyped_nullable: Vec<serde_json::Value>,
-            pub not_required_untyped: Vec<serde_json::Value>,
-            pub not_required_untyped_nullable: Vec<serde_json::Value>,
+            pub required_untyped: Vec<AnyType>,
+            pub required_untyped_nullable: Vec<AnyType>,
+            pub not_required_untyped: Vec<AnyType>,
+            pub not_required_untyped_nullable: Vec<AnyType>,
         }
 
         let mut intermediate_rep = IntermediateRep::default();
@@ -1319,10 +1319,10 @@ impl std::str::FromStr for ObjectUntypedProps {
 
             if let Some(key) = key_result {
                 match key {
-                    "required_untyped" => intermediate_rep.required_untyped.push(serde_json::Value::from_str(val).map_err(|x| format!("{}", x))?),
-                    "required_untyped_nullable" => intermediate_rep.required_untyped_nullable.push(serde_json::Value::from_str(val).map_err(|x| format!("{}", x))?),
-                    "not_required_untyped" => intermediate_rep.not_required_untyped.push(serde_json::Value::from_str(val).map_err(|x| format!("{}", x))?),
-                    "not_required_untyped_nullable" => intermediate_rep.not_required_untyped_nullable.push(serde_json::Value::from_str(val).map_err(|x| format!("{}", x))?),
+                    "required_untyped" => intermediate_rep.required_untyped.push(AnyType::from_str(val).map_err(|x| format!("{}", x))?),
+                    "required_untyped_nullable" => return std::result::Result::Err("Parsing a nullable type in this style is not supported in ObjectUntypedProps".to_string()),
+                    "not_required_untyped" => intermediate_rep.not_required_untyped.push(AnyType::from_str(val).map_err(|x| format!("{}", x))?),
+                    "not_required_untyped_nullable" => intermediate_rep.not_required_untyped_nullable.push(AnyType::from_str(val).map_err(|x| format!("{}", x))?),
                     _ => return std::result::Result::Err("Unexpected key while parsing ObjectUntypedProps".to_string())
                 }
             }
@@ -1334,7 +1334,7 @@ impl std::str::FromStr for ObjectUntypedProps {
         // Use the intermediate representation to return the struct
         std::result::Result::Ok(ObjectUntypedProps {
             required_untyped: intermediate_rep.required_untyped.into_iter().next().ok_or("required_untyped missing in ObjectUntypedProps".to_string())?,
-            required_untyped_nullable: intermediate_rep.required_untyped_nullable.into_iter().next().ok_or("required_untyped_nullable missing in ObjectUntypedProps".to_string())?,
+            required_untyped_nullable: std::result::Result::Err("Nullable types not supported in ObjectUntypedProps".to_string())?,
             not_required_untyped: intermediate_rep.not_required_untyped.into_iter().next(),
             not_required_untyped_nullable: intermediate_rep.not_required_untyped_nullable.into_iter().next(),
         })